Add fast Jellyfin library item counts

scene_search/jellyfin.py

@@ -122,6 +122,20 @@ class JellyfinClient:
 
         return results[:limit] if limit is not None else results
 
+    def item_count(self, library_id: str) -> int:
+        data = self._get(
+            "/Items",
+            params={
+                "ParentId": library_id,
+                "Recursive": "true",
+                "IncludeItemTypes": "Movie,Episode,Video",
+                "EnableTotalRecordCount": "true",
+                "StartIndex": 0,
+                "Limit": 1,
+            },
+        ).json()
+        return int(data.get("TotalRecordCount") or 0)
+
     def item(self, item_id: str) -> dict[str, Any]:
         data = self._get(
             "/Items",